1. Field of the Invention
The present disclosure relates generally to inkjet printing systems and more particularly a system and method for removing air from an inkjet cartridge and ink supply line therefor.
2. Description of the Background of the Invention
High-speed printing systems typically include one or more imaging units. Each imaging unit has one or more inkjet cartridges and a controller controls each inkjet cartridge to eject a fluid such as ink or other composition) onto a receiving surface. Each inkjet cartridge includes a nozzle plate that includes a plurality of orifices (nozzles) through which ink from inside the inkjet cartridge may be controllably ejected.
An inkjet cartridge typically includes a fluid chamber and one or more nozzles. Pressure inside of the fluid chamber is increased relative to ambient air pressure to force a drop of fluid through the nozzle(s). Some inkjet cartridges use a piezoelectric element that deforms a wall of the fluid chamber to reduce the volume thereof and thereby increase the pressure within the fluid chamber. Alternately, a heating element may be used to vaporize some of the fluid (or a constituent of the fluid such as a fluid carrier or a solvent) in the fluid chamber to form a bubble therein, which increases the pressure inside the fluid chamber. A controller controls the current that is passed through the piezoelectric element to control the deformation thereof or to control the current through the heating element in turn to control the temperature thereof so that drops are formed when needed. Other types of inkjet technologies known in the art may be used in the printing systems described herein.
In a printing system, an inkjet cartridge may be secured to a carrier and disposed such that the nozzles of the inkjet cartridge are directed toward the receiving surface. The carrier may be manufactured from steel or other alloys that can be milled to a high precision. More than one inkjet cartridge may be secured to a carrier in this fashion in a one or two-dimensional array. Moscato et al., U.S. Provisional Patent Application Ser. No. 61/523,079, filed Aug. 11, 2011, discloses one such apparatus and method for disposing inkjet cartridges in a carrier. Kanfoush et al., U.S. Provisional Patent Application No. 61/535,150 filed Sep. 15, 2011, discloses an apparatus and method for disposing an inkjet cartridge in a mount that may be secured to the carrier. The entire contents of U.S. Provisional Patent Application Nos. 61/523,079 and 61/535,150 are incorporated herein by reference.
Dried ink, dust, paper fibers, and other debris can collect on a nozzle plate or in a nozzle of an inkjet cartridge and prevent proper ejection of ink from the nozzles thereof. The controller of a printing system can undertake periodic cleaning cycles during which ink is purged from the nozzle to release any debris in or near such nozzle. The purged ink and/or debris must be removed from the nozzle plate in the vicinity of the nozzles so that such purged ink and/or debris does not collect thereon and dry to create further debris that will later interfere with ejection of ink from nozzles of the cartridge. Moscato et al., U.S. Provisional Application No. 61/685,002, filed Mar. 9, 2012, discloses a system and method of cleaning inkjet cartridges, the entire contents of which are incorporated herein by reference.
Ink is supplied to each inkjet cartridge from an ink reservoir via an ink line. If air becomes trapped in the ink line and flows into the fluid chamber of the inkjet cartridge during printing, such air may interfere with the proper ejection of ink from the nozzles of the inkjet cartridge.